Soldering Robot ?

Couldn't find a better area to put this, hope this is OK.

I am working on building a soldering robot. For a first try, I am just going to
make it an attachment to my Bridgeport mill, already controlled by LinuxCNC.
The X-Y platform is obvious, I have mounted a standard soldering iron
at an angle to a bar that goes into the spindle collet. It has a spring-
loaded arrangement allowing the soldering iron to retract along its
axis when the tip touches the PC board. Since it is mounted at an
angle, this also gives a slight wiping action as it retracts.
I'm hoping that mimics hand soldering to break through the oxide
film.

I have built a solder wire feeder. It has a Maxon gear motor and a
spring-loaded pinch roller (an instrument-size ball bearing on
a lever). This seems to work quite well, I was expecting tracking
and bunching problems, but it seems to be more robust than
I thought. I have just finished a control system for this that
advances the solder wire when a signal is present from the
CNC control, and then retracts the wire just a fraction of an
inch when the signal is shut off. The solder wire is fed toward
the soldering tip through a brass tube, and a longer plastic
tube delivers it from the feeder motor.

I think I can figure out how to extract X-Y coords from my PCB
CAD software (Protel 99) but I don't think it has a built-in
solder robot output file. I could copy the whole board,
delete anything that has a hole but doesn't need soldering
and then output the drill file, and convert the coordinates
from that file.

At each location, the quill would come down to Z=0 and then
dwell a moment, then feed solder wire for some time, then
stop the wire feed, dwell for some time, and then raise the Z.
That should be pretty easy to code up.

Anyway, is anyone else using LinuxCNC for a soldering robot
or similar application?

I will post some pictures when I get this hideous kluge
completely mounted to the machine.

Jon

Your PCB program should export a drill file (in addition to the Gerber artwork), which will contain the XY coordinates of each VIA hole. Typically it is sorted by drill size, so it should be easy to find the section that correlates with the plated thru-holes for leads.

You may find that you will have better luck duplicating a selective solder type machine that pumps molten solder up a tube from the bottom to form a 'point' solder wave (think like holding a garden hose vertically). The trick for materials selection is to use titanium for the tube and the solder pot and pump components (the solder will not stick to it, and it will not diffuse into the metal). Ive been considering building a type of 'pulse' pump that may be realistic for a hobbiest, that would function similar to one of those Nalgene squeeze bottle (often used in labs). The commercial ones are a continuous solder flow, but that is probably too much $$$ for the pump.

Anyway, I am looking forward to seeing this !

wanispissd wrote:

Your PCB program should export a drill file (in addition to the Gerber artwork), which will contain the XY coordinates of each VIA hole. Typically it is sorted by drill size, so it should be easy to find the section that correlates with the plated thru-holes for leads.

You may find that you will have better luck duplicating a selective solder type machine that pumps molten solder up a tube from the bottom to form a 'point' solder wave (think like holding a garden hose vertically). The trick for materials selection is to use titanium for the tube and the solder pot and pump components (the solder will not stick to it, and it will not diffuse into the metal). Ive been considering building a type of 'pulse' pump that may be realistic for a hobbiest, that would function similar to one of those Nalgene squeeze bottle (often used in labs). The commercial ones are a continuous solder flow, but that is probably too much $$$ for the pump.

Anyway, I am looking forward to seeing this !

Soldering robots (ie a soldering iron and solder wire feeder with an XY platform) are
standard gear, sold by a wide range of manufacturers. I am sure a selective solder
machine with a solder fountain may be faster, but it seems a lot of commercial work
is done with the robot-style machine. Since I do VERY small batches, like often
a dozen boards, the heat-up time, dross and clean-up with a fountain machine
sounds like a big hassle. Also, my scheme should be able to be changed over from
tin-lead to lead-free in a few minutes, the fountain machine probably could not be
changed over, you'd have to have two complete pot/pump/fountain systems.
Nicholas Benezan built a fountain machine from scratch, but it looks quite complicated.

So, I have reasons to prefer the robot soldering iron scheme.

Jon

Hi

As lazzy guy I use since many years emc BD2.xx on very rudimentary HW to do pcb's

Your idea to make a soldering robot is something I'll keep in mind for an upgrade........

Beginning from eagle export I needed a conversion tool running under windows to get G-code.

Have a look ...
Maybe it helps you to spare some time.

Mike